Art of producing side-gusseted bags



Feb. 3, 1959 P. MERCER ART' OF PRODUCING SIDE-GUSSETED BAGS Filed June 12, 1952 IN VEN TOR. x. Q

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2,871,771 ART OF PRODUCING SIDE GUSSETED BAGS Lewis P. Mercer, Inglewood, .Calif., assign'or to Milprint, Inc., Milwaukee, Wis, a corporation of Delaware Application June 12, 1952, Serial No. 293,189

2'Claims. (CI. 93-35) The present invention relates generally to improvements in the art of producing .bags, and relates more particularly to improvements in the construction of commcdity bags of the side gusseted type having animproved bottom closure and to the method of commercially producing such bags.

A primary object of this invention is to provide an improved side-gusseted flat-bottom bag formed of flexible sheet material and a highly efficient method of economically producing the same in large quantities and at low cost while effectively sealing the bottom closures thereof.

It has long been customary in the packaging industry to provide normally flat commodity bags formed of suitable sheet material and having inwardly folded side tucks or gussets and a sealed bottom, such bags being adapted for distention to prismatic shape upon insertion of a commodity so as to provide a relatively fiat rectangular base. The main advantages of commodity bags of this type are that they possess relatively large capacity, they are easy to open at the mouth portion for filling due to the side gussets and may therefore be filled by means of automatic machinery, and the flat base aids in maintaining the filled bags in upright position. How'- ever, one of the principal objections to these side-gusseted bags is the difiiculty encountered in the formation of the bottom closures and the inability to seal the bag bottoms with the aid of automatic machinery in a continuous bag production method so as to provide final commodity bag assemblages which are relatively inexpensive and which have sufiiciently strong and durable fiat bottoms to maintain the commodities packaged therein in wholesome and protected condition.

It is therefore a more specific object of the present invention to provide an improved side-gusseted bag and method of commercially producing the same which obviate the objections and disadvantages heretofore attendant this type of bag and production methods.

Another specific object of my invention is to provide an improved side-g'usseted commodity bag having a strong and durable bottom adapted to assume a relatively flat rectangular shape upon distention of the bag and in which the bag bottom is effectively sealed in a novel manner.

Another specific object of the invention is toprovide an improved method of continuously and automatically producing side-gusseted bags from a longitudinally-advancing web of sheet material with the aid of relatively standard equipment, the sidegussetsbeing sealed to the internal surface of the adjacent wall upon folding of the web into tubular formation.

Still another specific object of my present invention is to provide an improved commodity bag comprising, a flat tube of flexible material having gussets extending longitudinally along opposite sides between its outer walls, each of the gussets havinga fold thereof adhesively secured to the inner surface of theadjacent outer ,wall at a zone near one end of the tube with the tube end being 2,871,77l Patented Feb. 3, 195,9;

2 Y folded back upon itself along a fold line beyond the Zone and the adjacent surfaces of the outer walls being adhesively secured directly to each other.

An additional specific object of the present invention is to provide an improved method .of and apparatus for commercially producing large quantities of commodity bags such as hereinabove described from continuously advancing webs of sheet material in a most eflicient and economical manner.

These and other specific objects and advantages pf the invention will be apparent from the following'detailed description. s I

A clear conception of the several features constituting my present improvement, and ,of the steps ,of the improved method and apparatus for automatically .performing such steps may be had by referring'to the ,drawing accompanying and forming apartofthis specification, wherein like reference characters designate ,the same .or similar parts in the several views. 7

Fig. l is a more-or-less .diagrammatic top view illustrating the production steps ,of the method .of producing the improved side-gusseted bags from a web .of sheet material; j

Fig. 2 is a similarly diagrammatic side .view likewise illustrating the several production steps of .the improved method;

Fig. 3 is an enlarged fragmentary transverse section taken along the line 3--3 of Fig. 2;

Fig. 4 is a somewhat enlargedtransverse sectionthrough the tube immediately adjacent to the gusset seal but with the tube walls slightly separated .so sto more clearly reveal the structure; and I I r Fig. 5 is asimilarly enlarged plan viewof -,one.of:t he improved bags produced in accordance withmy method, a portion of the bottom closure flap beingiurned back and parts of the outer wall and gussets being brokenaway to more clearly reveal normally .hidden1structure While the improvements have been shown and described herein as being particularly applicable in izt h e production of-bags of the side-gusseted flat-bottomltype formed of regenerated cellulose or the like..and.espe cially adapted for packaging fine 'granularcommodities, it is not my desire or intention to ,thereby :unnecessarily limit the scope or utility of the invention, sincethe improvements may obviously'bezadvantageouslyapplied to other types of bags formedof any ,suitableflexible sheet .materials .for use in packaging diverse commodities; and it isalso contemplated that certain specific descriptive terms used herein shall'be giventhe broadest possible interpretation consistent with the disclosure.

In accordance with my present improved method of producing the improvedcommodity bags, I initially longitudinally advance a continuous-web or ribbon of suitable thin'and flexible sheet material along-a predetermined path. As the Web is thus. advanced, l applylocal laterally spaced spots of suitable adhesive material to one-face thereof inwardly of the ,side. edges of the web. :Simultaneouslywith the application of these adhesive ..-spo.ts or. immediately thereafter, I apply a continuous strip of suitable adhesiveto a longitudinal edge;portion -of;the advancing web. Thereafter l foldthe advancing web to form a-flat tube with; the longitudinal edgeportions of the web in overlapping relationship and the adhesive strip therebetween to form a longitudinal searn, the .op-

posite edges of the flattube being simultaneouslyiolded inwardly between'the outer walls of the tube tofform gussetsextendinglongitudinally along oppositesides with the adhesive spots positioned in spaced series between a fold of each gusset and the innersurface of "the adjacent outer wall. Next, the advancing tube is transversely severed adjacent to each set ofthe local adhesive spots to provide successivecorresponding tube sect-ionseach hav- Y ing a fold of each gusset adhesively secured at the local adhesive spots to the inner surface of the adjacent outer wall, the outer tube walls being preferably severed along offset transverse lines to provide an end tab of single thickness. A transverse strip of suitable adhesive is then applied to the inner surface of the end tab or extended wall of each of the successive tube sections between the adhesive spots and the adjacent severed end of each seci101]. Finally, the end portion of each tube section is folded back upon itself along a fold line above or beyond the adhesive spots with the transverse adhesive strip positioned between adjacent surfaces of the outer walls beyond the zone of the adhesive spots to secure the adjacent tube walls directlyto each other by means of the transverse strip to form a completed bag.

In the commercial exploitation of the improved bag production method hereinabove set forth, an apparatus substantially as diagrammatically shown in the drawing may be effectively utilized. Referring to Figs. 1 to 3 ofthe drawing, the Web or ribbon 8 of suitable flexible sheet material is initially supplied from a rotatably supported roll 9 over a series of rolls 10 of standard construction. As the web advances over the rolls 10, local laterally spaced spots 11 of adhesive are applied to one face thereof by means of a glue applying'roll 12 having raised surface portions 13 receiving glue or other adhesive from a glue transfer roll 14 operating in a glue pot 15. At the same time, a continuous adhesive strip 16 is applied to a longitudinal edge of the same face of the web 8 by suitable means, and this strip 16 may conveniently be applied by the same applicator roll 12 which need merely be formed with a raised peripheral portion 17 coacting with the edge portion of the web and with the glue transfer roll 14. The web 8 is than advanced over a tube forming unit 18v of standard construction which folds the Web to form a flat tube with the walls overlapped and sealed along the edge to form a longitudinal seam. Simultaneously, side gussets 19 are formed in the advancing tube by means of a pair of spaced longitudinally alined former plates 20, 21 of less width than the tube and having parallel side edges interiorly cooperable with the tube walls, the opposite side edges of the advancing tube being folded or tucked inwardly between the edges of the spaced plates 20, 21 by a pair of similar tuck plates 22 externally coacting with the tube. However, since the web 8 carries spaced spots 11 of adhesive on the surface which is folded to form the side gussets 19, means must be provided to maintain the inner surface of the adjacent outer wall of the tube spaced from the upper former plate during advancement of the tube so as to prevent the adhesive spots 11 from rubbing on and transferring to the plate 20; and for this purpose, a pair of spring wire spacers 23 are secured to the outer edges of the former plate 20 and coact with the outer tube wall adjacent to the successive adhesive spots 11 to maintain the wall away from the gussets. After the continuous gusseted tube has been formed, the tube may be flattened to secure the gusset folds bearing the adhesive spots 11 to the adjacent inner surface of the outer wall at these zones, and the tube is then severed into successive tube sections 24 adjacent to each set of spots 11 by means of suitable knives 25 of well-known construction, the lines of severance of the outer tube walls being preferably offset to provide an end tab or flap 26 of single thickness as shown. The transverse adhesive strip 27 may then be suitably applied to the inner surface of each end tab 26 between the spots 11 and the adjacent severed end by means of a suitable adhesive applicator such as roll 28 having a transverse glue applying projection 29 coacting with the tab 26 as it advances over a pressure roll 30. The successive tube sections 24 are then each formed into completed bag units byrnerely folding the end portion thereof back upon itself along a transverse fold line 31 beyond the adhesive spots 11 to cause the adhesive strip 27 to seal the tab 26 directly to the adjacent tube wall beyond the zone of the spots 11 as shown at 32 in Fig. 5.

Referring particularly to" Fig. 5, the improved bag formed in accordance with the improved method comprises, in general, a flat tube 24 of relatively thin flexible sheet material having inwardly directed gussets 19 extending longitudinally along opposite sides between its outer walls, each of the gussets 19 having a fold or pleat thereof adhesively secured to the inner surface of the adjacent outer wall by suitable adhesive spots 11 at a zone near one end of the tube 24 with the end of the tube being formed with an end tab or flap 26 of single wall thickness and being folded back upon itself along a fold line 31 above or beyond the zone defined by the spots 11 and the adjacent surfaces of the wall tab 26 and the other outer tube wall being adhesively secured directly to each other transversely thereacross beyond the zone of the spots 11 by a transverse adhesive strip 27.

From the foregoing detailed description, it is believed apparent that the present invention provides an improved side-gusseted commodity receiving bag which may be economically produced in large quantities and in a continuous manner through use of the improved production method and with the aid of relatively simple apparatus of more-or-less standard construction modified slightly to adapt the same to the improved method. In the production of the improved bags from a continuously advancing web 8, the glue spots 11 are applied together with the longitudinal edge strip 16 with the aid of a roll 12 having the glue applicator spots 13 spaced at predetermined localities, and as the web is advanced over the folding apparatus, these glue spots are effectively maintained away from the former plate 20 by means of spacer members 23. Upon folding of the bottom closure flap along the fold line 31, the flap 26 is effectively sealed to the side wall of the bag with the spots 11 effectively reenforcing the bottom of the bag by automatically sealing the one Wall of each gusset to the adjacent inner surface of the side wall, thereby also insuring against sifting of com modity from the bag bottom whenthe same is distended and filled with a commodity. As indicated hereinabove, the bags may be merchandised in large quantities in flat condition and may be readily opened at the mouth portion and filled with a commodity to expand the side gussets and provide a flat rectangular bottom or base for the final package, the bag bottom being effectively recnforced and sealed. The improved method and apparatus has been successfully employed in the actual commercial production of the improved gusseted bags for use in packaging diverse commodities, and the improved bags may actually be produced for approximately the same cost as prior bags of the same type which did not incorporate the improved bottom gusset or tuck seal.

It should be understood that it is not desired or intended to limit this invention to the exact steps of the improved method herein described or to the precise details of construction of the improved commodity bags, since various modifications within the scope of the appended claims may occur to persons skilled in the art to which this invention pertains; and it should also be understood that the improved bags may be decorated by printing or the like in the usual manner.

I claim: g

l. The method of producing gusseted bags from a web of flexible sheet material, which comprises, longitudinally advancing the web, applying a rectilinear series of local laterally spaced spots of adhesive to one face of the web inwardly of each of the side edges thereof, applying a continuous adhesive strip to a longitudinal edge portion of the same face of the advancing web, thereafter folding the web to form a tube having inwardly folded gussets extending longitudinally along opposite sides with a series of the adhesive spots disposed on one fold of each gusset and the outer walls being united to form a longitudinal seam, transversely severing said tube adjacent to but spaced from each set of said laterally spaced local spots to provide successive tube sections each having one fold of each gusset adhesively secured only at said adhesive spots to the inner surface of only the adjacent outer wall, applying a transverse strip of adhesive to a wall of each of said tube sections beyond and spaced from said setof adhesive spots and adjacent to the severed end of said section, and finally folding said end of each tube back upon itself along a transverse fold line located between its said set of adhesive spots and the other tube end to secure the adjacent surfaces of the outer tube walls directly to each other by means of said transverse strip to form a bag.

2. The method of producing gusseted bags from a web of flexible sheet material, which comprises, longitudinally advancing the web, applying a rectilinearly alined series of local laterally spaced spots of adhesive to one face of the web inwardly of each of the side edges thereof, applying a continuous adhesive strip to a longitudinal edge portion of the same face of the advancing web, thereafter folding the web to form a tube having the longitudinal edges united to form a seam extending along one wall and having inwardly folded gussets extending longitudinally along opposite sides with a series of the adhesive spots positioned only on the fold of each gusset 3 adjacent to the longitudinally seamed Wall, transversely severing said tube adjacent to but spaced from each set of said laterally spaced local spots to provide successive tube sections each having one fold of each gusset adhesively secured only at said adhesive spots to the inner surface of only the longitudinally seamed outer wall, applying a transverse strip of adhesive to the unseamed wall of each of said tube sections beyond and spaced from said set of adhesive spots and adjacent to the severed end of said section, and finally folding said end of each tube back upon the seamed wall along a transverse fold line located between its said set of adhesive spots and the other tube end to secure the adjacent surfaces of the outer tube walls directly to each other by means of said transverse strip to form a bag.

References Cited in the file of this patent UNITED STATES PATENTS 392,964 McCulla Nov. 13, 1888 1,983,291 Haskell Dec. 4, 1934 1,995,286 Arzet Mar. 26, 1935 2,085,301 Driver June 29, 1937 2,149,872 Schmidt Mar. 7, 1939 2,385,647 Poppe Sept. 25, 1945 

